I have a recording of a very talented guy singing 'Pie Jesu' at a wedding that I recently attended. Sadly a woman got up to use the bathroom a minute before he finished the song. As a result you can quickly hear the sound of her heels as she passes the camcorder. Is there a program that exists that can isolate the sound of the heels and remove it from the recording? Or have I watched one too many an episode of CSI?
There is a possibility to improve it slightly but it involves importing the video into an audio editing program (Sound Forge, Audition, Audacity, Logic, anything like that) and then altering the volume on each of her footsteps when the singer isn't singing. You will have to blend in "atmos" from the church to cover the silent breaks. If you try and take her footsteps out during the singing it will be noticeable. If you had hours, you can do it by cutting and pasting other parts of the singing and then blending them in over the footfall but the chances are that it will be obvious that "something" has been done to the audio.
What you might be able do, if you're lucky, is a bit of a cheat and only works if the singer is repeating a phrase. So, if he's sung the bit you want to clean up before, you copy the clean section and place it over the dirty bit on the timeline. Then fade from one to the other and back again. It only works on a chorus or for very short sequences and, you have to be lucky.
Can't think of anything else I'm afraid, as Tim Stannard so clearly puts it "you're trying to take flour out of a cake after you've baked it" or something like that.